1. Field of The Invention
The present invention relates to electric current-producing cells, and more particularly to such cells employing specified cathode-active materials of vanadium-chalcogen-containing compounds.
2. Description of the Prior Art
There has been considerable interest in recent years in developing high energy density batteries for voltaic cells. Exemplary of the developing systems is a high energy density electrochemical cell utilizing intercalation compounds of the transition metal chalcogenides, including vanadium dichalcogenides, as cathode-active materials and using alkali metal anodes, as set forth in U.S. Pat. No. 4,009,052. Cell data for VS.sub.2 and V.sub.x Fe.sub.1-x S.sub.2 (x .ltoreq. 0.5) cathodes showing less than or about one lithium per unit cathode material reversible capacity has recently been reported by Murphy et al. (Material Research Bulletin, Vol. 12, p. 825 et seq. (1977)) and by DiSalvo et al. (Bull. Am. Phys. Soc., Vol. 23, p. 244 et seq. (1978)). Also, the mineral patronite, VS.sub.4, has been investigated and found to have a capacity for less than one lithium and found to be irreversible by Murphy and Trumbore (Journal Crystal Growth, Vol. 39, p. 196 (1977)). U.S. Pat. No. 3,655,585 describes a cell utilizing as a cathode-active material vanadium pentoxide prepared by the thermal decomposition of ammonium vanadate.
The compounds utilized as the cathode-active materials in the cells of the present invention are vanadium-chalcogen-containing type compounds which show a surprisingly high capacity for lithium and are generally rechargeable. Further, notwithstanding the considerable variety of high energy density electrochemical cell systems which have recently been developed, it is believed that the particular cells of the present invention containing the vanadium-chalcogen-containing compounds have not been heretofore disclosed or rendered obvious.